At the time this book was first published the disciplines of philosophy of education, educational psychology, sociology of education and the history of education had developed rapidly. The papers in this volume outline the developments that took place. The first paper analyses the nature of a theory concerned with determining practice and the place of academic disciplines within that. What emerges is the crucial role of these disciplines, but also the need to develop much more adequately a domain of practical principles, assessed and critically reformulated in the light of those disciplines. The following papers are concerned with the contributions four of those disciplines are now making.